Optical and structural properties of bias sputtered vanadium pentoxide thin films

The effects of de bias on the optical and structural properties of dc magnetron sputtered vanadium pentoxide thin films are presented. It is shown that as the bias voltage is increased from 0 to -150 V the refractive index of the films goes through a maximum at -75 V and saturates thereafter. The highest refractive index obtained was 2.4 at a bias voltage of -75 V. The films are transparent in the region from 600 to 1500 nm for all bias voltages. Films which were amorphous up to a bias of -50 V transformed in to a crystalline phase at -75 V. They show the presence of tensile strain and a small change in grain size. (C) 1997 Elsevier Science Ltd. All rights reserved.